Electric lamp



(No Model.) 2 Sheets-Sheet 1.

A. T. GIFPORD.

ELECTRIC LAMP. .No. 351,973. Patented Nov. 2, 1886.

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ELECTRIC LAMP. ".No. 351,973. Patented Nov. 2, 1886.

' UNITED STATES PATENT OFFICE.

ALENZA T. GIFFORD, OF HOPEDALE, MASSACHUSETTS.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 351,973,da.ted November 2, 1886.

Application filed September 28, 1885. Serial No. 173,366. (No model.)

To aZZ whom it may concern:

Be it known that I, ALENZA '1. GIFFORD, of Hopedale, county of Worcester, State of Massachusetts, have invented an Improvement in Electric Lamps, of which the following description, in connection with the accompanying drawing is a specification, like letters on the drawings representing like parts.

My invention relates to a focusing electric lamp of that class in which the carbons have independent feeding devices; and it also relates to providing that class of electric lamps designed to maintain a continuous light with an automatic feeding device and with mechanism to supply fresh carbon pencils.

My invention consists, primarily, in the combination of the feeding device of one of the carbons with a circuitcontrolling device or switch operated by a thermal device affected by the heat radiating from the are, whereby the said feeding device is thrown out of operation when the end of the carbon reaches a certain point, thus determining the position of the are or luminous point, the said are being maintained at the proper length by the feed of the other carbon, which is controlled by variations in current strength dependent on the variations of the length of the are.

I have supplied my lamp with a double set of rolls, which constitute the feed mechanism for both the positive 'and negative carbons, and I operate these rolls by means of a train of gears placed on the arbors of the rolls, and gearing with each other in a manner to be hereinafter described.

I have pivoted upon one of the common arbors a lever having a pivoted pawl to engage the teeth of the gear on the same arbor as the lever, and I have connected the said lever by a link to the extended armature of the feedcontrolling magnet to operate the train of gears when the armature ot the said feed-controlling magnet is attracted. Upon the arbors ot' the upper set of rolls for feeding the positive carbon, and upon the arbors of the lower set of rolls for feeding the negative carbon, I have fastened two cams or dog-shaped arm's, which revolve with the said arbors, and, meeting each other, serve to move the upper positive and lower negative rolls one away from the other. I also employ a solenoid, wound cess in the frame of the lamp.

with coarse wire, in the main. circuit, and a feed-regulating and a feedc0ntro1ling magnet wound with fine wire in a shunt-circu1t around the are for the positive carbon, the same shuntcircuit containing a feed-regulating magnet for the negative carbon. As a holder for the can bons, I use a circular case having an inside and an outside wall, between which the carbons are placed, the said carbons being moved around'the circular space and into position to be engaged by the operating-rolls by means of indices secured to a rod provided with a spring and placed in the center of the said case, the said rod being free to turn in a re- I have extended the armatures of the feedregulating and feed-controlling magnets, and have provided them with insulated contact-pieces, the said contact-pieces cooperating with similar contact-pieces to make and break the circuit,

thereby alternately cutting out and cutting in the said feed-controlling and feed-regulating magnets in a manner to be described. In order to separate the carbons when the arc is established, I have provided the core of the main solenoid with an arm, which extends downward and is connected to a clamping-guide for the carbon pencils, the said clamping'guide being herein shown as a split tube, the said tube being split in order to grasp the rod tightly, and thus prevent the establishment of a small are between the metal of the said tube and the carbon rod.

In my invention asolenoid wound with coarse wire is placed in the main'circuit, and the feedcontrolling and feed regulating magnet is placed in a shunt-circuit around the carbons, the armatures of the sh u nt-magnets being pro vided with terminals cooperating with similar terminals secured to the frame-work of the lamp, to alternately open and close their circuits, and the core of the maincircuit solenoid is provided with an extension or arm connected to the split carbon-holding tube or guide to lift the said split tube and confined carbon, to establish the are when the current traverses the main-circuit solenoid, the said tube or guide being split to insure good electrical connection between it and the carbon pencil.

Figure 1 in section and elevation shows part of an electric lamp embodying my invention.

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Fig. 2 is an enlarged detail showing the operating device of the thermal switch; Fig. 3, a plan view of Fig. 2; Fig. 4, an enlarged detail of the circuit-closer; Fig. 5, a plan view of my improved lamp with the top of the lamp removed; and Fig. 6 an enlarged sectional detail of the upper part of the lamp, the said figure showing some of the parts omitted from Fig. 1, the top of the carbon-holding case and which is herein shown as a train of gears operating two sets of rolls, thereby causing the said carbon a to be fed downward in proportion as the arc is lengthened by the consumption of the carbons. The lower carbon, a", is also provided with alike feed mechanism actuated by a magnet, B, in the shuntcircuit with the magnet B, the said magnet 13 tending to produce a constant feed of the said carbon while it is in circuit, the said feed being faster than the amount consumed from the said lower carbon, thus tending continually to raise the same and the luminous point or are at the end thereof, the said up ward feed being controlled by a thermal device which shunts the magnet B by closing a shunt-circuit when the said thermal device is operated upon by the heat radiating from the rising are, thereby stopping the upward feed of the said carbon. The magnet B, included in the shunt-circuit S, is controlled by another shunt, S, the terminals of the said shunt S being connected, respectively, with the members 6 e of an electric switch or circuit closer, (see Figs. 1 and 4,) the said members being normally disconnected from one another, causing the current to traverse the magnet B and the latter to maintain the feed of the lower carbon in operation.

In order to stop the feed of the lower carbon, 0, when its upper end arrives at the to cal point or place where it is desired to maintain the are, the lamp is provided with a thermal device, shown in this instance as consist ing of a ring, f, supported on a suitable arm or bracket, f, and composed of two materials, as shown in Fig. 8, having different rates of expansion by heat, the inner portion being, for instance, brass, and the outer portion iron or steel. The said ring is cut across at one point, as shown atf, (see Fig. 3,) so that when its temperature is raised the rate of expansion at the interior is greater than at the exterior of the ring, and will-cause the latter to open or expand, widening the space f. The ring at one side of the spacef has pivoted upon it a long arm or lever, 9, connected near its pivot g by a link, g, with the ring at the other side of the space f as clearly shown in Figs. 2 and 3, so that the expansion of the ring, as just described, will effect a much greater oscillation at the upper end of the lever or arm thus enabling the end of the said lever, which is located near the ends of the members 0 e of the circuit-closer, to be moved into position between the said members and into contact with both of them, thus making 2 an electrical connection from one to the other,

thereby shunting the magnet B, so that the feed of the lower carbon, 0", ceases.

The ring f encircles the upper carbon, a, at a short distance above the point at which the are is to be maintained, as shown in Fig. 1, in which position the radiant heat from the arc is sufficient to raise the temperature of the said ring to the point at which the lever g closes the circuit at e c, throwing the magnet B out of operation, and as the lower carbon, 0, is consumed, removing the are from the ring f, the latter will become cooler and will contract, causing the lever g to move away from the circuit-closers c e, leaving them electrically disconnected, and thus causing the current to traverse the magnet B, which will then actuate the feed mechanism of the carbon 0, raising it until the arc is brought to the proper point, when its heat will expand the ring f sufficiently to again arrest the feed of the lower carbon.

To enable the lamp to present an unbroken light, I fill the space between the outer and inner walls of the ease E with carbon pencils a, and I move the said pencils into position to be engaged by the rolls 1) b by means of pointers or indices 0 c, which are secured to a rod, t, provided with a spring, 8, to turn it, one

end of the said spring being connected with the said rod and the other with the framework, as shown in Fig. 6. The rolls 1) b in suitable bearings have two cams or dog-shaped arms, a a fastened to and revolving with their arbors, and the said cams, being longer than the distance between the centers of the two rolls b b, the said rolls will be forced apart when the said arms come in line between the centers of the said rolls. The rolls 1) b and I) b are operated by a train of gears, of which the large gear in on the arbor of the roll b co-operates with the large gear m on the arbor of the roll ZF. The small gear it, also on the arbor of the roll I), cooperates with the gear a on the arbor of the roll I). The gear a on the arbor of the roll If cooperates with the gear a on the arbor of the roll Z). Thus it will be seen that the gears m and m, a and n, a and n cooperate, and that n and a and a and a do not cooperate. In order to operate the train of gears and the double set of rolls, I have pivoted a lever, L, upon the arbor common to'the roll I) and the gear m, and have connected the said lever by a link, Z, to the extended armature d of the feed-eontrolling magnet B, so that the said train of gears and double set-s of rolls will rotate and feed the carbon when the said armature d is attracted,

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the said rolls being prevented from rotating backward by a pawl, 11, pivoted upon the said lever and engaging the teeth of the gear m.

The action of the feed-controlling magnet B is governed by the magnet D, wound with fine wire and having an armature, d, provided with an insulated contact-piece, c, the said contact-piece forming one terminal of a circuitcloser, the other terminal, 0, being fastened to the frame of the lamp in any convenient position, but insulated from it. The armature d of the magnet B also has attached to it an insulated contact-piece, 0 forming one terminal of a circuit-closer, the other terminal, 0, be ing attached to the frame of the lamp, but insulated from it.

To obtain the best possible contact between the carbon pencil a and the carbon-holding tube H, I have split the said tube almostits entire length to the point 8", as shown in Fig. 6, and I have connected the said tube at the point a by solder or other suitable means, to an arm, Ir, of the core a of the solenoid A, the said arm being connected to the said core by a screw,

In lamps of this class as heretofore used the carbon pencils when fed down, made an imperfect contact with the carbon holding tube, so that a small are was oftentimes established between the said pcnciland tube, thereby-throwing a considerable resistance into the circuit of the lamp.

My improved lamp is provided at its lower part or bottom with mechanism to operate the negative carbon in the same manner as the positive is operated, the said mechanism consisting of a feed controlling magnet, gears, rolls, lever, and connecting-link, being substantially the same as that herein described and used in connection with the positive carbon, and in practice the negative carbon will be renewed by means ofacarbon-holding case, (not shown,) but the same as that described in connection with the positive carbon.

The operator, when charging the carbonholding case E with carbon pencils, turns the rod i, by means of the pointer c, in an opposite direction to that in which it is turned by the action of the spring 8, so that the said carbon pencils and pointers will he in the position indicated by Fig. 5, the said spring opcrating to force the carbons, by means of the pointers 00, into position to be engaged by the rolls 6 b.

When the lamp is not burning, the carbons are in contact. When the current flows through the lamp, it divides, the greater part flowing through the solenoid A, causing it to attract its core a thereby raising the arm I)", the carbon-holding tube H and its inclosed carbon pencil a passing to the tube H and pen cil a. to establish the are. A second portion of the current passes through the feed-regulating magnet D, by way of the circuit-closer c 0, while a third portion of the current passes through the feed-controlling magnet B,wl1en the circuit-closer c c is open and the one 0 0 traction of the core for its armature d, and

closing the circuit 00 y at 0'0", thus putting the magnet B into circuit. As the magnet B becomes magnetized, its armature d is attracted, breaking the circuit 50* 1/ at c c, and cutting out the magnet D. When the armature d is attracted,it moves upward the link Z and lever L, thereby inoving the gears and rolls in the direction of the arrow. As the gears are revolved, the cams or dog shaped arms a c, acting as before described,are turned with them, and the said arms, being longer than the distance between the centers of the rolls when revolved into line between the said centers, exert a pushing force upon the arbors of the rolls 1) 1), thereby spreading the said rolls apart and allowing the carbon to be pushed between them by the indices 0 a into posit-ion to be fed down by the rolls 1) b, which, being without the said cams, are not spread apart. As soon as the carbon has reached the point where the normal arc is again estab lished, the current flowing through the solenoid A is strengthened, and the core a again attracts the armature d away from the magnet D, thereby breaking the circuit .90 y at c a, cutting out the magnet, B, which, becoming demagnetized, no longer attracts its armature d, whereby the said armature drops and closes the circuit 00 y at c 0, thereby putting the magnet D into circuit. As the armature (1 drops, the link land lever L drop down, and a spring pressing against the rolls 1) b, but not herein shown, causes them to again bind on the carbon pencil. As the lever L is moved down, the gear at would naturally move back ward; but it is prevented from so doing by the pivoted pawl 19, which engages a tooth of the said gear. If the upper carbon should be a poor one, and should consequently be rapidly consumed, the action of the feedcontrolling magnet B and the feed-regulating magnet D would be continuous.

I claim- 1. In an electric lamp, a feeding device for one of the carbons, combined with an automatic feed-controlling device operated by the heat of the are to stop the feed of said carbon when said are arrives at a point near said thermal device, and operated by the decrease in heat of the arc to permit the said carbon to be fed when said are has receded from said thermal device, substantially as described.

- 2. In an electric lamp, a feeding device for one carbon controlled by changes in current strength produced by changes in the arc-resistance, combined with a feeding device for the other carbon,and electro-magnet operating the said feeding device continuously while in circuit, acircuitcontrolling device for the said magnet, and thermal device operated by the heat from the are by which the said circuitcontrolliug device is operated, substantially as described.

3. In an electric lamp, the solenoid A in the main circuit. the feed-controlling magnet B and the feed-regulating magnet D in a shunt-circuit, the said shunt-magnets having armatures provided with terminals 0 c of circuit-closers, and co-operatiug with corresponding terminals, c" c, to operate substantially as described.

t. The carbou-holding case, pivoted rod, and pointers carried thereby, and a spring to turn said rod, combined with one or more pairs of feed-rolls, between which the carbon pencils are moved by the said pointers, and with cams or dog shaped arms to spread apart said rolls, and with a train of gears to rotate said rolls to feed the carbon pencils, snbstantially as described.

In an electric lamp, the solenoid A, the feed-controlling magnet B, and the feed regulating magnet D, combined with the arm I), and the clamping tube or guide connected therewith and inclosing the carbon pencil, the said tube firmly grasping the said carbon pencil, thereby securing good electrical contact between the tube and pencil, substantially as described.

6. The carbonholding ease, pivoted rod, and pointers carried thereby, and a spring acting upon the said rod to move the carbon pencils into position to be engaged by feedrolls, combined with a train of gears and feedrolls, and cams or dog-shaped arms to spread apart the rolls, and a pivoted lever carrying a pawl, the said lever being connected to the armature of the feed-controlling magnet, to operate substantially as described.

7. In an electric lamp, the solenoid A, mag net D, its armature d, and the magnet B and its armature (I, combined with the link Z, lever L, gears I) b I)" b, arms a a", and pawl p, to operate substantially as described.

8. In an electric lamp, the carbon-feeding rolls 1) b and their boxes, combined with cams or dog-shaped arms to separate the said rolls for the entrance of a carbon, substantially as described.

9. In an electric lamp, the carbon-holding ease, pivoted rod, and pointer carried thereby, and a spring to turn said rod, combined with the feed-rolls, the gearing to operate said L rolls, cams or dog-shaped arms to move apart said rolls, and with a clamping-guide to re ceive the carbon pencils from said feedrolls, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ALENZA T. GIFFORD.

Vita esses:

J AMES H. CHURCHILL, W. H. Sros'rorv. 

